This invention relates to the casting of molten metals, and more particularly the continuous vertical casting of metal parts, in particular pipes, of cast iron. Although it applies to the casting of different types of metal parts, it is particularly advantageous for the casting of thin-walled cast iron pipes. The expression "thin-walled pipes" applies to pipes of small thickness/diameter ratio, less than 10%, rather than the thickness considered by itself in isolation.
The invention relates more particularly to a machine for the continuous vertical casting along a vertical extraction axis of cast iron pipes comprising a die block aligned with the vertical extraction axis and a device for the supply of liquid iron feeding the die, a machine in which at least one sealing gasket is located between the outlet from the supply device and the inlet to the die.
In order to ensure a satisfactory seal at the gasket or gaskets it is necessary to apply a certain tightening force to them parallel to the axis of extraction of the pipes. This force should act against the force extracting the pipes in order to compress the sealing gaskets and thus ensure a seal for the whole.
When a casting machine is brought up to steady state conditions, the various materials in contact with the liquid metal expand by different proportions according to the material. This expansion affects the tightening of the sealing gaskets, so the gaskets can be damaged and/or the seal for the liquid metal may be lost.
Difficulties of the same kind may result from creep of the gaskets over time, and also their adhesion to the pipe die during the course of manufacture.